Low severity · published Oct 22, 2026
CVE-2026-115386
Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Memory Disclosure via fd_readdir
New
2.6
CVSS
0.2%
EPSS
No
On KEV
Description
Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an information disclosure vulnerability in the WASIp1 fd_readdir implementation that copies uninitialized struct padding into guest memory. Guests with a preopened directory can list entries to receive three bytes of leftover host stack or heap memory per directory entry.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
Required
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 9% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WA
wasmtime · bytecodealliance
before 36.0.17; 37.0.0 before 48.0.4; 49.0.0 before 49.0.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-115386
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-115386
github.com
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-96f6-r43r-8c24
www.vulncheck.com
https://www.vulncheck.com/advisories/wasmtime-before-36.0.17-37.0.0-before-48.0.4-and-49.0.0-before-49.0.2-memory-disclosure-via-fd-readdir
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